Retired Col. Robert Friend, former director of the Air Force's nearly 20-year UFO study, Project Blue Book, says that science should continue looking into the mystery of flying saucers.

Friend, assigned in 1958 to direct Blue Book, was charged with trying to determine if UFOs were a threat to national security and whether they could be of scientific interest.

"When I first took over the program, I wrote two staff studies, and in both instances, I recommended that [UFOs] be put into another agency which would give them full scientific investigations and analyses," Friend told The Huffington Post over the weekend at a special lecture titled "Military UFOs: Secrets Revealed."

The event, held at the Smithsonian-affiliated National Atomic Testing Museum in Las Vegas, featured Friend, seen below, three other retired military colonels and a former United Kingdom Ministry of Defense UFO investigator.

LAS VEGAS -- Former Air Force Col. Charles Halt accused the federal government of a UFO cover-up that involves a secret agency to deal with what might be extraterrestrial visitations.

"I'm firmly convinced there's an agency, and there is an effort to suppress," Halt told an audience of 200 people Saturday night at the Smithsonian-affiliated National Atomic Testing Museum.

Two former Air Force officers who were part of the infamous Project Blue Book -- the military's official UFO investigation in the 1950s and '60s -- and a former investigator with Britain's Ministry of Defense were among the panel of speakers for a program entitled "Military UFOs: Secrets Revealed."